The human mammary carcinoma cell line, MCF-7, can be propagated in a serum-free medium consisting of Improved Eagle's Minimal Medium (IMEM)-zinc option supplemented with EGF (10 ng/ml), insulin (10 Mug/ml), transferrin (10 Mug/ml) and Pedersen fetuin (1 mg/ml) or fibronectin (0.5 to 1 Mug/well) on type I collagen (0.5 Mug/well) or with Holme's alpha-one glycoprotein (200 ng/well) on type IV collagen (0.5 Mug/well). Cell growth under these conditions is comparable to that in medium containing 10% fetal calf serum. The purpose of these studies is two-fold: 1. to determine whether various hormones, growth factors or vitamins might enhance or modulate the expression of some of the cell surface, tumor-associated antigens on MCF-7 cells using monoclonal antibodies which were generated against surface antigens on human breast tumor samples and 2. to correlate the expression of these antigens on MCF-7 cells and several clonal lines derived from these cells with: 1. production of TGF's; 2. EGF and estrogen receptor status; 3. type IV collagen ad laminin production and 4. growth rate. Three well characterize antibodies will be utilized: B72.3, B6.2 and B139. Expression and quantitation of these antigens will be accomplished by using a live cell radioimmunoassay and indirect immunofluoreescence. Studies to date indicate that the expression of the three antigens are different but comparable for any one antigen with cells grown in the absence or presence of serum. Moreover, the level of antigen expression was comparable for any one antigen whether the cells were propagated on type I or type IV collagen. The various MCF-7 cell clones differ in both EGF receptor levels, TGF production and antigen expression.